Y-shaped beam splitters for self-collimated beams in 2D photonic crystals

In this paper, a new Y-shaped beam splitter is designed by combining the partial band gap with self-collimation in a two-dimensional photonic crystal, and the design has been validated by infinite-difference time-domain simulation. Simultaneously, we improve the design and enhance the power transmission ratio by inserting an air trench into the incident waveguide. The transmission rises from 24% to 44% at the normalized frequency of 0.185 in each branch, and the maximum transmission ratio within the frequency range of self-collimation reaches 47% at the normalized frequency of 0.187.